Trolley systems are a common way to transport workpieces, tools, etc. from one location to another in a manufacturing environment. Typically, the system includes a load carrying platform mounted on trolley wheels. A track is laid out to guide the trolley wheels along a desired path.
The trolley wheels generally include an outer race, an inner race, and ball bearings disposed therebetween to permit rotation of the outer race about the inner race. The ball bearings require a large amount of lubricant in order to operate properly. In addition, the bearings must be protected from outside contaminants such as dirt which can cause premature failure of the assembly. Accordingly, sealing assemblies are provided to seal the lubricant within the trolley wheel and protect the wheel from contaminants.
There are inherent problems associated with trolley wheel sealing assemblies. Due to the relative movement between the inner and outer races, a rigid sealing connection cannot be made between the races. Rather, sealing members extending from the inner and outer races are joined in slidable friction engagement to create a seal therebetween. However, the friction engagement between the seals produces wear after substantial use which reduces the integrity of the seal as time passes.
One way to reduce the wear between the sealing members is to make the sealing member extending from the inner race rotatable thereabout. That is, by mounting the inner race sealing member in a rotatable fashion about the inner race, a portion of the rotational momentum of the outer race sealing member will be imparted to the inner race sealing member. There will be less relative motion between the sealing members because of the rotation of the inner race sealing member, thus producing less slidable resistance between the sealing members. Accordingly, there will be less wear produced by the slidable friction engagement between the sealing members. However, this will produce wear on an inner circumferential edge of the inner race sealing member as it rotates about the inner race. This is troublesome as a small increase in the inner diameter of the inner race sealing member can affect the integrity of the seal.